Adjustable chair



March 22, 1966 E. w. NYBERG ETAL 3,241,880

ADJUSTABLE CHAIR Filed March 31 1964 6 Sheets-Sheet 1 "MINIMUM INVENTORS. ERNESTW/VYBERG JOHN H WILLIAMS Z ZZQ/Q @M March 22, 1966 E. w. NYBERG ETAL 3,241,880

ADJUSTABLE CHAIR 6 Sheets-Sheet 2 Filed March 31, 1964 INVENTORS. ERNEST W NYBERG JOHN 0. WILL/A M5 d 4 Q0 Q 0 0d TH E1 H ER March 22, 1966 T .1. JUST riled March 51 1964 E CHA s-sheet s Elilii March 22, 1966 E. w. NYBERG ETAL 3,241,880

ADJUSTABLE CHAIR 6 Sheets-Sheet 4 Filed March 31, 1964 6% b1 mi INVENTORS. ERNEST W /V R6 BOH/V 0. WILZ/Z /QS M March 1966 E. w NYBERG ETAL 3,

ADJUSTABLE CHAIR Filed March 31, 1964 6 Sheets-Sheet 5 Illllll Illa? INVENTOR ERNESTW NYBE G R Q BY JOHNOW/LL/AMS M/QQMM Th EZRFH-Z March 1966 E. w. NYBERG ETAL 3, ,8

ADJUSTABLE CHAIR Filed March 31, 1964 6 Sheets-Sheet 6 INVENTORS. ERNEST W NYBERG JOHN D. WILLIAMS cwf gw Th E'TZE EH 5 United States Patent 3,241,880 ADJUEiTABLE CHAIR Ernest W. Nyherg, Morton Grove, ML, and John ll). Wiiiiams, 6860 3rd Ave, Kenosha, Wis; said Nyberg assignor to said Williams Filed Mar. 31, 1964-, Ser. No. 356,149 16 Claims. (@l. 297-302) This invention relates to a chair and, more particularly, to an office chair embodying a yieldable back rest which may be used in business ofiices and like place and which is sometimes known as an executive" chair.

Ofiice chairs having yieldable back rest constructions have been made and used heretofore and among these have been chairs embodying coil spring mechanisms for yieldably tensioning and restraining the back rest of the chair and for resetting or returning the back rest into its normal position after each rearward flexing operation thereof. However, such prior chairs have been subject to a number of disadvantages and among these has been the fact that many of them are complicated in construction and expensive to manufacture. In addition certain of such prior chairs have employed an exposed coil spring resetting mechanism in which the clothing of the occupant may become entangled in the use of such chairs so that such chairs are somewhat dangerous in operation and objectionable in use.

Accordingly, an object of the present invention is to provide a new and improved and relatively simple and inexpensive ofiice or business chair and which is so designed, constructed and arranged that the tensioning and resetting mechanism for the back rest is concealed, and the operating parts thereof are not exposed so that the clothing of the occupant will become entangled therein, to the end that the new chair is entirely safe in operation and in no way dangerous to the occupant.

An additional object of the invention is to provide a novel back rest tensioning and resetting mechanism in the new chair and novel means for adjusting the tension of the back rest tensioning and resetting mechanism.

An additional object of the present invention is to provide a new and improved mechanism for operatively connecting the seat of the new chair and the yielding back rest in such a manner that the weight of the occupant of the new chair acts upon and through the back rest thereof to raise the front end portion of the chair slightly so as to exert a slight upward lift on the legs of the occupant of the chair to add to his comfort.

A further object of the invention is to provide a chair embodying the novel combinations of elements hereinafter recited and claimed.

Other objects of the invention will appear hereinafter.

In the drawings:

FIG. 1 is a perspective view of a chair embodying the present invention, as seen from the rear thereof;

FIG. 2 is a side elevational view of the new chair as shown in FIG. 1;

FIG. 3 is a fragmentary elevational view of a part of the back rest tensioning and resetting mechanism embodied in the new chair;

FIG. 4 is a central vertical sectional view on line 4-4 in FIG. 2 showing part of the back rest tensioning and resetting mechanism embodied in the new chair;

FIG. 5 is a perspective view illustrating the operating mechanism of the new chair in assembled position, a part thereof being broken away to reveal certain of the operating parts thereof;

FIG. 6 is a central vertical sectional view on line 6-6 in FIG. 3 showing the part of the operating mechanism of the new chair;

FIG. 7 is a bottom plan view of the operating mechanism embodied in the new chair;

FIG. 8 is a transverse sectional plan view on line 8-8 of FIG. 6 showing parts of the back rest tensioning and resetting mechanism embodied in the new chair;

FIG. 9 is a transverse sectional plan view on line 9-9 in FIG. 6 showing a part of the back rest tensioning and resetting mechanism embodied in the new chair;

FIG. 10 is a sectional view on line 1010 in FIG. 7 showing the pivotal connection between the seat-supporting unit and the L-shaped seat-operating and back rest tensioning and resetting unit which are embodied in the operating mechanism of the new chair;

FIG. 11 is a transverse sectional detail view on line 1111 in FIG. 7 showing parts of the operating mechanism embodied in the new chair;

FIG. 12 is a view on line 1212 in FIG. 7, partly in side elevation and partly in section, illustrating parts of the operating mechanism embodied in the new chair;

FIG. 13 is an enlarged sectional detail view of FIG. 13 circled in FIG. 6 showing part of the back rest tensioning and resetting mechanism embodied in the new chair;

FIG. 14 is a fragmentary sectional view, partly in elevation, on line l t-14 in FIG. 7, illustrating parts of the seat operating and back rest tensioning and resetting mechanism embodied in the new chair; and

FIG. 15 is an exploded perspective view showing the principal parts of the seat operating mechanism and back-rest tensioning and resetting mechanism embodied in the new chair.

A preferred embodiment of the new chair is illustrated in the drawings, wherein it is generally indicated at 20, and comprises a caster-bearing supporting base structure 21 which includes a centrally arranged screw-threaded elevation adjusting and supporting post member 22. The seat unit of the new chair is generally indicated at 23 in the drawings and includes a horizontally extending portion 24 and side wall or arm rest portions 25, and a seat cushion 26 which is adapted to be arranged upon the seat unit 23, as best shown in FIG. 1. A back rest cushion unit 27 is arranged between the side or arm rest portions 2525 and aback rest tensioning and resetting mechanism, generally indicated at 28, is associated therewith, and will be described in detail hereinafter.

The operating mechanism for the new chair is generally indicated at 29 in the drawings and comprises a relatively stationary supporting frame unit 30 which is shown as being generally channel-shaped in form and includes a pair of parallel side wall or rail members 31 between which, adjacent one end thereof, a bracing member 32 is arranged (FIG. 15). A hole 33 is provided in each of the side wall or rail members 31 adjacent one end thereof, those holes 33 being aligned with each other for a reason which will be explained hereinafter. A block 34- is disposed between and is fastened to the side walls or rails 31 of the relatively stationary member 30 and this block 34 has the upper end portion of the screwthreaded elevation adjusting and supporting post member 22 mounted therein so that the relatively stationary unit 30 is thus attached to and is carried by the supporting post 22. A generally U-shaped supporting bracket 35 is rigidly attached to the front end portions of the side rails 31 of the relatively stationary member 30, for a reason which will be pointed out hereinafter.

The operating mechanism 29 for the new chair includes a combination seat operating and back-rest operating unit, which is generally indicated at 36, and is generally L shaped in form (FIG. 15), and includes a pair of parallel side wall members or rails 37 each of which is provided with a hole 38 between the ends thereof. Each of the side rail members 37 is also provided with a hole 39 adjacent to the front end portion thereof, the holes 3338 and 3939 being aligned in pairs, for reasons which will be pointed out hereinafter.

The combination seat operating and back rest operating unit 36 includes, as a part thereof, the upwardly extending back rest operating unit 28.

The back rest operating unit 28 includes a housing portion 40 which is formed, in part, as an integral upward extension of the side rails 37 of the L-shaped unit 36 (FIG. and this housing 40 includes a rear .wall portion 41, a front wall portion 42, and side wall portions 43. Adjustably mounted within the housing 40 is a back-rest tensionadjusting member 44 which is generally U-shaped in crosssection (FIG. 8) and includes a rear wall 45 and side wall 46.

A single latch opening 47 is formed in the rear wall 41 of the unit 40 and a vertically extending row of latch openings 48 is formed on the rear wall 45 of the back rest tension-adjusting member 44 (FIGS. 4 and 6).

A latch carrier member 49 is mounted within the body of the housing 40, and is attached to the lower end portion 78 of a plate 77, and the upper end portion of plate 77 is attached, as by a screw 79, to the front wall 42 of the housing 40 (FIGS. 6, 14 and 15). This latch carrier member 49 has a latching detent 50 slidably mounted therein and this latching detent 50 is urged, by a coil spring 51, which is carried by the latch carrier member 49, into latching engagement with and into a selected one of the latch openings 48 in the rear wall 45 of the back rest tension-adjusting member 44 and into the single latch opening 47 in the rear wall 45 of the housing unit 40 so as to latch the back-rest tension-adjusting member 44 and the body of the unit 40 together, (FIGS. 6, 8 and 14), for a purpose which will be explained hereinafter.

The operating mechanism 29 for the new chair includes a seat-supporting unit 52 which embodies a pair of parallel side rail members 53 each of which has a notched rear end portion 54 (FIGS. 12 and 15). Each of the side rail members 53 also has a notched portion 55 provided therein in its bottom edge between the ends thereof (FIGS. 6, 12, 14 and 15), for the reception of the bracket 35. Each of the side rails 53 of the unit 52 has a somewhat angularly upwardly inclined front end portion 56 having a hole provided therein, and a pivot member 57 is inserted therethrough for the purpose of pivotally mounting the seatsupporting unit 52 upon the L-shaped unit 36, as will be described more fully hereinafter.

The seat-supporting unit 52 includes a seat-supporting and attaching plate member 58 which is preferably formed integrally with the side rails 53 of the unit 5 2, or the plate 58 may be secured to the side rails 53 in any suitable manner, as by being welded to the upper surfaces of the side rails 53. The plate member 58 is provided with slots 59 through which fastening elements in the form of screws or bolts 60 may be inserted to attach the plate 58 to the base 24 of the seat-supporting unit 2324.

The L-shaped unit 36 includes a back-rest tensioning and resetting mechanism, generally indicated at 62, and which includes certain of the parts hereinbefore described including the back rest tension-adjusting member 44, the latch carrier 49, the latching detent 50 carried thereby, and the spring 51 which urges the latching detent 50 into latching engagement with a selected one of the latch holes 49 in the tension adjusting member 44 and into the single latch hole 47 in the upwardly extending portion 40.

The L-shaped unit 36 is pivotally interconnected to the seat-supporting unit 52 by means of a pivot construction 61 which is best shown in FIG. 10. This pivot construction includes an anchoring block 62 which extends between the side rails 37 of the L-shaped unit 36. A hearing bushing 81 is provided in the hole 38 in each of the side rails 37 and a bolt 64 is extended through each of these bearing bushings 81 into a tapped opening in the anchoring block 62 of the pivot unit 61 (FIG. 10).

The pivot unit 57, which pivotally interconnects the front end portions of the side rails 37 of the L-shaped unit 36 with the front end portions 56 of the side rails 53 is similar in construction .to the pivot unit 61, as hereinbefore described.

The back-rest tension and resetting mechanism 62, includes a pair of tubular guide members 63 which are arranged within the portion 40 and within the member 44 which is mounted therein. Each of these members 63 extends through an opening 64 in the latch carrier member 49, and the member 49 is slidably mounted upon the members 63. To this end each of the members 63 has a pair of aligned and axially extending slots formed therein and guide pins 65 carried by the member 49 extend into and work in these slots 80 in the members 63, (FIGS. 4 and 8). Each of the members 63 has an outwardly extending annular flange 66 at its lower end (FIGS. 4, 6, l3 and 15 and a back-rest tensioning and resetting expansion coil spring 67 is arranged around each of the members 63. Each of these springs 67 has an upper end portion which bears against the bottom wall of the latch carrier member 49 and each has a lower end portion which bears against the annular outwardly extending flange 66 of the corresponding tubular guide member 63.

An internally threaded tubular member or ferrule 63 (FIG. 4) is fixedly mounted in the lower end portion of each of the tubular guide members 63 and the upper end portion of a screw-threaded adjustable spring tensioning rod 69 is threadedly mounted in each of these ferrules 68 (FIG. 4). Each of these rods 69 has an unthreaded lower end portion 70 which extends through an opening 71 which is formed in a pivot pin member 72 which extends through and is pivotally mounted in the holes 33 in the rear end portions of the side rails 31 of the relatively stationary supporting unit 39 and in the notched rear end portions 54 of the side rails 53 of the seat-supporting and attaching unit 52. Each of the reduced lower end portions 70 terminates in a tool-receiving lower end portion 73 of reduced diameter (FIGS. 4, 7 and 13).

As shown in FIG. 14, the lower end portion of the front wall 42 of the upright rear portion 40 of the combination seat operating and back-rest operating unit 36 terminates, as at 74, above the horizontal portion thereof so as to provide an access opening to the upright extension 40, and a protective closure cap member 75, which is generally U-shaped in cross-section (FIG. 9) is removably mounted in the lower end portion of the upright extension 40 of the L-shaped operating unit 36 so as to close the access opening to the upright extension 40.

The back rest cushion 27 is pivotally connected, as at 76 to the tension-adjusting member 44 (FIGS. 3, 4 and 6) so as to permit the back rest cushion 27 to pivot slightly upward relative to the parts 40-44.

In the use of the new chair the weight of the occupant upon the seat cushion 26 acts, through the seat cushion 26 and the seat frame 24 to pivot the L-shaped unit 36 upon the pivot unit 61 (counterclockwise from full to dotted line position, FIG. 2) relative to the relatively stationary supporting unit 30 which is carried by the upright supporting post 22. During this operation the L-shaped operating unit 36 and the parallel side rails 37 thereof also pivot upon the pivot unit 57, relative to the seat-supporting unit 52, and the spaced parallel arms 53 thereof, by reason of the pivotal interconnection 57 between the parallel side rails 37 of the unit 36 and the parallel side rails 53 of the seat-supporting unit 52 (FIG. 10). This pivotal movement of the unit 36 acts, through the pivotal interconnection 57 between the unit 36 and the seat-supporting unit 52, to pivot the front end portion of the unit 52 and the seat frame 24 and the seat cushion 26 carried thereby slightly upwardly, (from full to dotted line position, FIG. 2), thereby exerting a slight upward lift on the legs of the occupant of the chair and thus adding to the comfort of the occupant of the chair.

At the same time, that is, when the weight of the occupant of the chair causes the L-shaped operating unit 36 to pivot, (counterclockwise from full to dotted line position, FIG. 2), the resulting rearward and downward movement of the portion 40 acts to compress the tensioning and resetting coil springs 67. This action is best understood by a comparison of FIGS. 6 and 14 of the drawings and is as follows: As the L-shaped operating unit 36 is thus pivoted rearwandly on the pivot unit 61, relative to the relatively stationary supporting unit 30, the screwthreaded tension-adjusting rods 69, and attached ferrules 68 and tubular guide members 63, and the coil springs 67 thereon, pivot on and with the pivot pin member 72 due to the mounting of the lower end portions 70 of the rods 69 in the openings 71 in the pivot pin member 72 while, at the same time, the rods 69, ferrules 68, members 63 and coil springs 67 thereon, are restrained, by the mounting of the member 72 in the rear end portions of the side rails 31 of the unit and in the notched rear end portions 54 of the side rails 53 of the unit 52, from moving downwardly with and relative to the upwardly extending housing portion of the L-shaped operating unit 36, and the back-rest tension-adjusting member 44 carried thereby, and which pivots rearwardly and downwardly with the extension 40.

During this operation, the parts move from the position in which they are shown in FIG. 6 into the position in which they are shown in FIG. 14, and from the position in which they are shown in full lines in FIG. 2 into the position in which they are shown in dotted lines in FIG. 2. As the back-rest units 36 and 44 are thus moved rearwardly and downwardly the latch carrier member 49 slides downwardly upon and relative to the tubular guide members 63, which are restrained from vertical movement, as pointed out above, and the member 49 is slidably guided on the members 63 by the engagement of the guide pins 65 carried thereby in the axially extending slots 80 in the members 63. This downward movement of the member 49 upon and relative to the members 63 compresses the resetting coil springs 67 which are arranged upon the members 63, between the bottom surface of the member 49 and the outwardly extending annular flanges on the upper end portions of the spring tensionadjusting screw rods 69.

During this operation the rods 69 and the members 63 carried thereby, (being restrained from downward movement by the pivot pin member 71 which interconnects these parts with the relatively stationary supporting unit 30 and with the seat-supporting unit 52) pivot as a unit with and upon the pivot pin member 71 which pivots in the openings 33 of the side rails 31 of the unit 30 and in the notched rear end portions 54 of the side rails 53 of the unit 52.

The springs 67 are thus compressed between the latch carrier member 49 and the outwardly extending annular flanges 66 on the lower end portions of the members 63, and when the weight of the occupant of the chair is shifted forwardly, so as to remove the pressure on the back rest cushion 27, the then compressed tensioning and resetting coil springs 67 expand and the force exerted thereby acts against the bottom wall of the latch carrier member 49 and the outwardly extending annular flanges 66 on the lower end portions or the tubular guide members 63 acts to pivot the L-shaped operating unit 36, relative to the relatively stationary supporting unit 30 and the seat-supporting unit 52, (clockwise, from dotted to full line position, FIG. 2), or from the position in which the parts are shown in FIG. 4 into the position in which the parts are shown in FIG. 6. As this operation takes I place the latch carrier member 49 slides upwardly on the members 63 into its raised position, as in FIG. 6.

During the resetting operation, as referred to above, the seat-supporting unit 52 pivots upon the pivot unit 57, relative to the L-shaped unit 36, back into its normal position, and the seat frame 24, side arms 25, seat cushion 2t) and back rest 27 are thus returned to their normal position, as in full line, FIG. 2.

It will be noted that the coil springs 67 function both as resetting springs for the L-shaped operating unit 36 and as tensioning spring means for tensioning the back rest 27 and attached operating parts 40-44, etc., for the new chair so that the back rest 27 has at all times a certain degree of flexibility relative to the seat unit 24 and seat cushion Z6 and side arms 25 of the new chair.

In the use of the new chair, the tension of the tensioning and resetting coil springs 67 may be readily adjusted. This is accomplished by inserting a suitable tool, such as a screw driver, into the single latch opening 47 in the rear wall 41 of the upward extension 46 so as to press the latching detent 50 inwardly against the force of the spring 51, so that the tension-adjusting member 44 is thus unlatched from latching engagement with the upright extension 46. The member 44 and attached plate member 77-78, and latch carrier member 49 and back rest cushion 27 may then be manipulated up or down in and relative to the housing 40 so as to vary the tension on the springs 67, whereupon the back rest cushion 27, back rest tensioning member 44, and attached plate member 77-78, and the latch carrier member 49 may be latched in the desired adjusted position by engaging the latching detent 56 in a selected one of the latch openings 48 in the rear wall 45 of the member 44 and in the single latch opening 47 in the rear wall 41 of the back rest housing 40.

A further adjustment of the back rest tensioning and resetting coil springs 67 may be accomplished by attaching a suitable tool, such as a pair of pliers, to the lower end portions 73 of the screw-threaded tension-adjusting rods 69 and rotating the latter in and relative to the screwthreaded ferrules 68 in which the upper end portions thereof are mounted, so as to raise or lower the tubular guide members 63 upon and relative to the spring tension-adjusting rods 69 and thus vary the overall or axial length of the tubular guide members 68 and attached spring tension-adjusting screw members 69, and the compression of the coil springs 67.

Thus, if the tension-adjusting rods 69 are rotated in a direction to lower the members 63 on and relative to the rods 69, the spring tension-adjusting rods 69, being unable to move upwardly or downwardly due to their mountings in the pivot pin member 72, will rotate in their openings 71 in the pivot pin member 72, and thus shorten the overall length of the rods 69 and the members 63 carried thereby. This adjustment of the tensionadjusting rods 69 and the tubular guide members 63 will compress the coil springs 67 and increase the tension and the resetting force exerted thereby in use. Conversely, if the rods 69 are rotated in the ferrules 68 in a direction to lengthen the overall length of the rods 69 and attached members 63 the tension-ing and resetting coil springs 67 will be allowed to expand between the lower surface of the latch carrier member 49 and the annular outwardly extending flanges 66 on the lower end portions of the tubular guide members 63 and the tensioning and resetting force of the coil springs 67 will thus be reduced.

The protective closure member '75 may be readily removed from the open lower end portion 74 of the front wall 42 so as to permit access to the interior of the housing 40 for the purpose of repair or replacement of the operating parts therein.

It will be noted that in the use of the new chair the working parts of the L-shaped unit 36 and the parts of the relatively stationary supporting unit 39, and the parts of the seat-supporting unit 52, are arranged within and concealed Within the side rails 37 of the L-shaped unit 36 and that the working parts of the back rest tensioning and resetting mechanism 284tl 44 are all arranged within and concealed in the housing portion 40-44 of unit 36 so that there is no likelihood of the working parts of the new chair coming in contact with the clothing or with the body of the occupant of the chair.

In addition, the new chair is comfortable in use since the upward lift of the front end portion of the seat frame 24 and seat cushion 26 on the legs of the occupant of the chair, when the occupant leansrearwardly against the back rest cushion 27, adds to the comfort of the user. Moreover, the back rest unit, being placed under tension of the springs 67, as described above, further adds to the comfort of the user of the new chair.

It will thus be seen from the foregoing description, considered in conjunction with the accompanying drawings, that the present invention provides a new and improved chair having the desirable advantages and characteristics and accomplishing its intended objects including those hereinbefore pointed out and others which are inherent in the invention.

We claim:

1. A chair comprising a supporting frame including an upright post, a seat unit and a back-rest unit, a relatively stationary supporting unit attached to and carried by the said post, a seat-supporting unit attached to the said seat unit at the bottom of the latter, a combination seat-operating and back-rest operating unit including an elongated generally horizontally extending portion below the said seat unit and an upwardly extending rear portion extending upwardly at the rear of the said back rest unit and attached thereto, means pivotally interconnecting the said horizontally extending portion between the ends thereof with the said stationary supporting unit, and means pivotally interconnecting the front end portion of the said horizontally extending portion with the front end portion of the said seat-supporting unit forwardly of the said first-named pivotal connection.

2. A chair as defined in claim 1 in which the said pivotal interconnection between the said combination unit and the said stationary supporting unit is disposed forwardly of the said post and between the latter and the said last-named pivotal interconnection.

3. A chair as defined in claim 1 in which the said combination unit is generally L-shaped in form and in which the said generally horizontally extending portion and the said upwardly extending rear portion thereof are rigidly interconnected together for movement as a unit upon and relative to the said first-named .pivotal interconnection.

4. A chair as defined in claim 1 in which the said horizontally extending portion of the combination unit includes a pair of spaced substantially parallel side rail members, and in which the said seat supporting unit includes a pair of spaced substantially parallel side rail members arranged in parallel relation with and between the said first mentioned parallel members.

5. A chair as defined in claim 1 in which the said horizontally extending portion of the said combination unit includes a pair of spaced substantially parallel side rail members, and in which the said seat-supporting unit includes a seat-attaching plate member attached to the said seat unit at the bottom of the latter, and in which the said seat-supporting unit includes a pair of spaced substantially parallel side rail members attached to and depending from the said seat-attaching plate member and arranged in parallel relation with and between the said first mentioned parallel members.

6. A chair as defined in claim 1 in which the horizontally extending portion of the said combination unit includes a pair of spaced substantially parallel side rail members, and in which the said seat-supporting unit includes a seat-attaching plate member attached to the said seat unit at the bottom of the latter, and also includes a pair of spaced substantially parallel side rail members attached to and depending from the said seat-attaching plate member and arranged in parallel relation with and between the said first mentioned members and in which the said stationary supporting unit includes a pair of spaced side rail members extending substantially parallel to and between the said spaced side rail members of the said seat-supporting unit.

7. A chair as defined in claim 1 in which the horizontally extending portion of the said combination unit includes a pair of spaced substantially parallel side rail members, and in which the said seat-supporting unit includes a seat-attaching plate member attached to the said seat unit at the bottom of the latter, and a pair of spaced substantially parallel side rail members attached to and depending from the said plate member and arranged in parallel relation with and between the said first-named rail members, and in which the said stationary supporting unit includes a pair of spaced side rail members extending substantially parallel to and between the said last-named rail members and in which the said post is screw-threaded, and in which the said stationary supporting unit has an anchoring portion extending between the said spaced side rail members thereof and having the said post threadedly and adjustably mounted therein.

8. A chair as defined in claim 1 in which the said combination unit is substantially L-shaped in form and in which the said upwardly extending rear portion thereof is in the form of a housing, and in which the said chair includes back-rest tensioning and resetting spring means coacting with the said generally L-shaped operating unit for tensioning the said upwardly extending rear portion thereof and the said back rest unit attached thereto and for returning the said generally L-shaped operating unit to its initial and normal position after each rearward pivotal movement thereof upon and relative to the said first-named pivotal interconnection.

9. A chair as defined in claim 1 which includes backrest tensioning and resetting spring means arranged within the said upwardly extending rear portion of the said combination unit, a spring tension adjusting member adjustably mounted within the said upwardly extending rear portion and having the said back rest unit attached thereto, and spring tension adjusting means adjustably mounted within the said upwardly extending rear portion for adjusting the tension of the said spring means.

10. A chair as defined in claim 1 which includes backrest tensioning and resetting spring means arranged within the said upwardly extending rear portion of the said combination unit, a spring tension adjusting member adjustably mounted within the said upwardly extending rear portion and having the said back-rest unit attached thereto, latch means within the said upwardly extending rear portion for latchingly engaging the said spring tension member and the said rear portion together for movement as a unit, and spring tens-ion adjusting means adjustably mounted within the said rear portion and for adjusting the tension of the said spring means.

11. A chair as defined in claim 10 and in which the said spring tension adjusting means includes a pair of spaced tubular guide members arranged within and extending longitudinally of the said upwardly extending rear portion and having the said latch means slidably mounted thereon, a pair of screw-threaded spring tensioning rods adjustably mounted within the said upwardly extending rear portion below the said members, means adjustably interconnecting the upper end portions of the said rods with the lower end portions of the said members, a backrest tensioning and resetting coil spring mounted on each of the said members, and additional means for pivotally mounting the lower end portion of the said rods in the rear end portion of the said stationary supporting unit and said seat-supporting unit so that the said rods and the said members and the said coal springs are restrained from upward and downward movement relative to and during movement of the said combination unit but are free to pivot rearwardly and forwardly with the said rear portion of the said combination unit on the said additional means.

12. A chair as defined in claim 11 and in which the said spring tension adjusting means includes a pair of spaced members arranged within and extending longitudinally of the said rear portion and having the said latch means slidably mounted thereon, a pair of screw-threaded spring tensioning rods adjustably mounted within the said upwardly extending rear portion below the said members, means adjustably interconnecting the upper end portions of the said rods with the lower end port-ions of the said members, a back-rest tensioning and resetting coil spring mounted on each of the said members, and additional means for pivotally mounting the lower end portions of the said rods in the rear end portions of the said stationary supporting unit and said seat-supporting unit so that the said rods and the said members and the said coil springs are restrained from upward and downward movement relative to the said combination unit but are free to pivot rearwardly and forwardly with the said rear portion of the said combination unit on the said additional means, and in which each of the said members has an annular outwardly extending annular flange formed thereon at the lower end thereof, and in which each of the said tensioning and resetting coil springs is mounted on one of the said members between the said latch means and the said flange.

13. A chair as defined in claim 12 and in which the said spring tension adjusting means includes a pair of spaced members arranged within and extending longitudinally of the said rear portion and having the said latch means slidably mounted thereon, a pair of screwthreaded spring tensioning rods adjustably mounted within the said rear portion below the said members, means adjustably interconnecting the upper end portions of the said rods with the lower end portions of said members, a tensioning and resetting coil spring mounted on each of the said members, and additional means for pivotally mounting the lower end portions of the said rods in the rear end portions of the said stationary supporting unit and said seat-supporting unit so that the said rods and the said members and the said coil springs are restrained from upward and downward movement relative to the said combination unit but are free to pivot rearwardly and forwardly with the said rear portion of the said combination unit on the said additional means, and in which each of said rods has a tool-receiving lower end portion extending downwardly below the said rear portion for adjusting the said rods relative to the said members so as to vary the tension of the said coil springs.

14. A chair comprising a supporting frame, a back rest unit and a seat unit carried by the said frame, a combination seat-operating and back-rest operating unit, means pivotally mounting the said combination unit upon the said frame for pivotal movement of the said units in a vertical plane relative to the said frame, and means carried by the said back rest unit and cooperating with the said combination unit for tensioning the said back rest unit during each rearward pivotal movement thereof and for resetting the said units after each rearward pivotal movement thereof.

15. A chair comprising a supporting frame structure, a back rest unit and a seat unit carried by the said frame structure, a combination seat-operating and back-rest operating unit, means for pivotally mounting the said combination unit upon the said frame structure for pivotal movement of the said units in a vertical plane relative to said frame structure, back rest tensioning and resetting spring means carried by the said back rest unit, means coacting with the said combination unit for tensioning the said spring means during each rearward pivotal movement, seat-attaching means carried by and attached to the said seat unit on the bottom side of the latter, and means pivotally interconnecting the said seat-attaching means and the said combination unit adjacent the front end portion of the said combination unit for limited pivotal movement thereof in a vertical plane.

16. A chair as defined in claim 15 in which the said second pivot means is located forwardly of the said first pivot means.

References Cited by the Examiner UNITED STATES PATENTS 1,929,023 10/ 1933 Hickman 297-302 2,778,409 1/ 1957 Soderberg 297304 2,818,911 1/1958 Syak 297-303 FRANK B. SHERRY, Primary Examiner. 

1. A CHAIR COMPRISING A SUPPORTING FRAME INCLUDING AN UPRIGHT POST, A SEAT UNIT AND A BACK-REST UNIT, A RELATIVELY STATIONARY SUPPORTING UNIT ATTACHED TO AND CARRIED BY THE SAID POST, A SEAT-SUPPORTING UNIT ATTACHED TO THE SAID SEAT UNIT AT THE BOTTOM OF THE LATTER, A COMBINATION SEAT-OPERATION AND BACK-REST OPERATING UNIT INCLUDING AN ELONGATED GENERALLY HORIZONTALLY EXTENDING PORTION BELOW THE SAID SEAT UNIT AND AN UPWARDLY EXTENDING REAR PORTION EXTENDING UPWARDLY AT THE REAR OF THE SAID BACK REST UNIT AND ATTACHED THERETO, MEANS PIVOTALLY INTERCONNECTING THE SAID HORIZONTALLY EXTENDING PORTION BETWEEN THE ENDS THEREOF WITH THE SAID STATIONARY SUPPORTING UNIT, AND MEANS PIVOTALLY INTERCONNECTING THE FRONT END PORTION OF THE SAID HORIZONTALLY EXTENDING PORTION WITH THE FRONT END PORTION OF THE SAID SEAT-SUPPORTING UNIT FORWARDLY OF THE SAID FIRST-NAMED PIVOTAL CONNECTION. 